Unleash is an open-source feature management platform. Prior to 8.0.3, FeatureEventFormatterMd.format in src/lib/addons/feature-event-formatter-md.ts assigns Mustache.escape to an identity function before rendering action and path templates. Because Mustache.escape is process-wide, the assignment disables escaping for subsequent Mustache.render calls in email-service.ts, webhook.ts, datadog.ts, and new-relic.ts. An editor-level user can place Slack or Microsoft Teams link syntax in an unrestricted username, trigger a feature event, and inject an attacker-labeled link into a trusted outbound notification channel, while other Mustache sinks remain unescaped until restart. This issue is fixed in version 8.0.3.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-116"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63466.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "8.0.3"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "002012cfdbedd2e9b7db9dc83b9f549f761db22e"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v8.0.3",
"range": [
{
"fixed": "ebb398aeeefaf3bb8b4020237d1b706462d1a00e"
}
],
"source": "REFERENCES_TAG"
}
]
}